A typical AC or DC motor has a shaft or individual rotor driving a gear reducer, or sprocket, for example, or other structure.
Motor brakes are used to hold a load stationary, to brake a load, for soft stop braking, or the like. Many brakes employ a friction disk keyed to the motor shaft. The friction disk rotates between two plates one of which is fixed and the other of which is axially driven by spring pressure. Electromagnets are energized when the motor is on compressing the spring and releasing the pressure on the friction disk. When the motor is de-energized, the electromagnets are also de-energized and the spring driven plate presses the friction disk between the two plates.
These and other powered brakes for motor drives often require a large amount of space within the drive system as well as additional wiring and power.